Low Cost Plug-in Powertrain: Plug-in for the Mass Market

摘要

Plug-in Hybrid Electric Vehicles (PHEV) contribute to fulfill the car manufactures CO_2 emission fleet targets. Currently, parallel (P2 and P4) and power-split PHEV are in series production, but most of them are offered for a much higher price than vehicles with conventional powertrains using combustion engines only. Many alternative powertrain concepts are discussed and evaluated in literature. This paper presents an innovative concept, which mainly reduces the cost of the powertrain system dedicated to price sensitive markets like China. This is achieved by combining several approaches. First of all, the electric machine design is not compromised by established package constraints and the torque and speed range of a combustion engine. For this investigation it is designed as induction machine (IM) for an optimal benefit-to-cost ratio. Secondly, the electrified powertrain is used to simplify the transmission. The conventional launch element and the reverse gear are removed because the powerful electric drive system facilitates the vehicle maneuvering forward and backward. Furthermore, mechanical synchronizers in the gearbox are not necessary anymore, because the synchronization is done by the coordination of electric drive and combustion engine. Last but not least, the number of gears for the transmission is reduced to a minimum. This gearbox is an application for a Dedicated Hybrid Transmission (DHT) [1]. Thirdly, a cost efficient MPI combustion engine (MPI engine: Multipoint Injection or PFI engine: Port Fuel Injection) is proposed. With this approach, all typical vehicle requirements and use cases of a conventional car are covered while its costs are significantly lower than that of established PHEV powertrains. In this paper the design of the proposed powertrain concept is evaluated by simulation.